<template>
    <div class="app-container">
        <h2 style="text-align: center;">发布新课程</h2>
        <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
            <el-step title="填写课程基本信息"/>
            <el-step title="创建课程大纲"/>
            <el-step title="最终发布"/>
        </el-steps>

        <el-form label-width="120px">
            <el-form-item label="课程标题">
                <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
            </el-form-item>

            <!-- 所属分类 TODO -->
            <el-form-item label="课程分类">
                <!-- 一级分类 -->
                <el-select
                    v-model="courseInfo.subjectParentId"
                    placeholder="一级分类" @change="subjectLevelOneChanged">
                    
                    <el-option
                    v-for="subject in subjectOneList"
                    :key="subject.id"
                    :label="subject.title"
                    :value="subject.id"/>
                </el-select>

                <!-- 二级分类 -->
                <el-select v-model="courseInfo.subjectId" placeholder="二级分类" @change="$forceUpdate()">
                    <el-option
                        v-for="subject in subjectTwoList"
                        :key="subject.id"
                        :label="subject.title"
                        :value="subject.id"/>
                </el-select>
            </el-form-item>

            <!-- 课程讲师 TODO -->        
            <!-- 课程讲师 -->
            <el-form-item label="课程讲师">
                <el-select
                    v-model="courseInfo.teacherId"
                    placeholder="请选择">

                    <el-option
                    v-for="teacher in teacherList"
                    :key="teacher.id"
                    :label="teacher.name"
                    :value="teacher.id"/>
                </el-select>
            </el-form-item>

            <el-form-item label="总课时">
                <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
            </el-form-item>

            <!-- 课程简介 TODO -->
            <el-form-item label="课程简介">
                <tinymce :height="300" v-model="courseInfo.description"/>
            </el-form-item>

            <!-- 课程封面 TODO -->
            <!-- 课程封面-->
            <el-form-item label="课程封面">
                <!-- 
                自动上传
                :show-file-list 显示文件列表
                :on-success     上传成功
                :before-upload  上传之前    
                :action         接口地址
                 -->
                <el-upload
                    :show-file-list="false"
                    :on-success="handleAvatarSuccess"
                    :before-upload="beforeAvatarUpload"
                    :action="BASE_API+'/eduoss/fileoss'"
                    class="avatar-uploader">
                    <img :src="courseInfo.cover">
                </el-upload>
            </el-form-item>


            <el-form-item label="课程价格">
                <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
            </el-form-item>
            <el-form-item>
                <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
            </el-form-item>
        </el-form>
    </div>
</template>

<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce' //引入组件

export default {
    //声明组件
    components: { Tinymce },

    data() {
        return {
            saveBtnDisabled:false,  //保存并下一步按钮是否禁用
            courseInfo:{
                title: '',
                subjectId: '',//二级分类id
                subjectParentId:'',//一级分类id
                teacherId: '',
                lessonNum: 0,
                description: '',
                cover: '/static/02.png',
                price: 0
            },
            courseId:'',
            BASE_API: process.env.BASE_API, // 接口API地址
            teacherList:[],//封装所有的讲师
            subjectOneList:[],//一级分类
            subjectTwoList:[]//二级分类
        }
    },
    created() {
        this.init()
    },
    watch: { //监听
        $route(to, from) { //路由变化方式，路由发生变化，方法就会执行
            this.init()
        }
    },
    methods: {
        init(){
            //获取路由id值
            if(this.$route.params && this.$route.params.id){
                this.courseId = this.$route.params.id
                //调用根据id查询课程的方法
                this.getInfo()
            }else{
                //初始化所有讲师
                this.getListTeacher()
                //初始化一级分类
                this.getOneSubject()
                //清空表单
                this.courseInfo = {}
                this.courseInfo.cover =  '/static/02.png'
                // this.courseInfo.lessonNum = 0,
                // this.courseInfo.price = 0
                // this.description=''
            }
        },
        //根据课程id查询
        getInfo(){
            course.getCourseInfoId(this.courseId)
                .then(response => {
                    //在courseInfo课程基本信息，包含 一级分类id 和 二级分类id
                    this.courseInfo = response.data.courseInfoVo
                    //1 查询所有的分类，包含一级和二级
                    subject.getSubjectList()
                        .then(response => {
                            //2 获取所有的一级分类
                            this.subjectOneList = response.data.list

                            //3 把所有的一级分类数组进行遍历
                            for(var i=0;i<this.subjectOneList.length;i++){
                                //获取每个一级分类
                                var oneSubject = this.subjectOneList[i]
                                //比较当前courseInfoVo里面一级分类id和所有的一级分类id
                                if(this.courseInfo.subjectParentId == oneSubject.id){
                                    //获取一级分类所有的二级分类
                                    this.subjectTwoList = oneSubject.children
                                }
                            }
                        })
                    //初始化所有讲师
                    this.getListTeacher()
                })
        },
        //上传封面成功调用的方法
        handleAvatarSuccess(res, file){
            this.courseInfo.cover = res.data.url
        },
        //上传之前调用的方法
        beforeAvatarUpload(file){
            //文件的类型
            const isJPG = file.type === 'image/jpeg'
            //文件的大小
            const isLt2M = file.size / 1024 / 1024 < 2
            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },
        //点击某个一级分类，触发change，显示对应二级分类
        subjectLevelOneChanged(value){
            //value就是一级分类id值
            //遍历所有的分类，包含一级和二级
            for(var i=0;i<this.subjectOneList.length;i++){
                //每个一级分类
                var oneSubject = this.subjectOneList[i]
                //判断：所有的一级分类id 和 点击一级分类id是否一样
                if(value === oneSubject.id){
                    //从一级分类获取所有的二级分类
                    this.subjectTwoList = oneSubject.children
                    //把二级分类id值清空
                    this.courseInfo.subjectId = ''
                }
            }
        },
        //查询所有的一级分类
        getOneSubject(){
            subject.getSubjectList()
                .then(response => {
                    this.subjectOneList = response.data.list
                })
        },
        //查询所有的讲师
        getListTeacher(){
            course.getListTeacher()
                .then(response => {
                    this.teacherList = response.data.items
                })
        },
        //添加课程
        addCourse(){
            course.addCourseInfo(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '添加课程信息成功!'
                    });
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/' + response.data.courseId})
                })
        },
        //修改课程
        updateCourse(){
            course.updateCourseInfo(this.courseInfo)
                .then(response => {
                    //提示
                    this.$message({
                        type: 'success',
                        message: '修改课程信息成功!'
                    });
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/' + this.courseId})
                })
        },
        saveOrUpdate(){  
            //判断添加还是修改
            if(!this.courseInfo.id){
                //添加
                this.addCourse()
            }else{
                //修改
                this.updateCourse()
            }
        }    
    },
}
</script>

<style scoped> /* scoped表示这个样式只在当前页面有效 */
    .tinymce-container {
        line-height: 29px;
    }
</style>